dm thin: cleanup noflush_work to use a proper completion

Factor out a pool_work interface that noflush_work makes use of to wait
for and complete work items (in terms of a proper completion struct).
Allows discontinuing the use of a custom completion in terms of atomic_t
and wait_event.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

1 files changed, 34 insertions, 18 deletions

diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 242ac2ea5f29..7694988fb806 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -1610,47 +1610,63 @@ static void do_no_space_timeout(struct work_struct *ws)
 
 /*----------------------------------------------------------------*/
 
-struct noflush_work {
+struct pool_work {
         struct work_struct worker;
-        struct thin_c *tc;
+        struct completion complete;
+};
+
+static struct pool_work *to_pool_work(struct work_struct *ws)
+{
+        return container_of(ws, struct pool_work, worker);
+}
+
+static void pool_work_complete(struct pool_work *pw)
+{
+        complete(&pw->complete);
+}
 
-        atomic_t complete;
-        wait_queue_head_t wait;
+static void pool_work_wait(struct pool_work *pw, struct pool *pool,
+                           void (*fn)(struct work_struct *))
+{
+        INIT_WORK_ONSTACK(&pw->worker, fn);
+        init_completion(&pw->complete);
+        queue_work(pool->wq, &pw->worker);
+        wait_for_completion(&pw->complete);
+}
+
+/*----------------------------------------------------------------*/
+
+struct noflush_work {
+        struct pool_work pw;
+        struct thin_c *tc;
 };
 
-static void complete_noflush_work(struct noflush_work *w)
+static struct noflush_work *to_noflush(struct work_struct *ws)
 {
-        atomic_set(&w->complete, 1);
-        wake_up(&w->wait);
+        return container_of(to_pool_work(ws), struct noflush_work, pw);
 }
 
 static void do_noflush_start(struct work_struct *ws)
 {
-        struct noflush_work *w = container_of(ws, struct noflush_work, worker);
+        struct noflush_work *w = to_noflush(ws);
         w->tc->requeue_mode = true;
         requeue_io(w->tc);
-        complete_noflush_work(w);
+        pool_work_complete(&w->pw);
 }
 
 static void do_noflush_stop(struct work_struct *ws)
 {
-        struct noflush_work *w = container_of(ws, struct noflush_work, worker);
+        struct noflush_work *w = to_noflush(ws);
         w->tc->requeue_mode = false;
-        complete_noflush_work(w);
+        pool_work_complete(&w->pw);
 }
 
 static void noflush_work(struct thin_c *tc, void (*fn)(struct work_struct *))
 {
         struct noflush_work w;
 
-        INIT_WORK_ONSTACK(&w.worker, fn);
         w.tc = tc;
-        atomic_set(&w.complete, 0);
-        init_waitqueue_head(&w.wait);
-
-        queue_work(tc->pool->wq, &w.worker);
-
-        wait_event(w.wait, atomic_read(&w.complete));
+        pool_work_wait(&w.pw, tc->pool, fn);
 }
 
 /*----------------------------------------------------------------*/